Auxiliary spark-gap.



F. F. HULTGREEN.

AUXILIARY SPARK GAP.

APPLICATION FILED NOV-1,1915.

Patented Sept. 18, 1917.

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- ing the reduce Parana @FFJIGE- FRANK F. HULTGREEN, OF BERKELEY, CALIFORNIA.

AUXILIARY SPK-GAIP.

Specification of Letters Patent.

Patented Sept. ltd, 1911?.

Application filed November 1, 1915. Serial No. 59,025.

To all whom it may concern:

Be it known that I, FRANK F. Hun'rennnn, a citizen of the United States, residing at Berkeley, in the county of Alameda and State of California, have invented certam new and useful Improvements in A uml ary Spark-Gaps, of which the following is a specification. J,

This inventidn relates to an improved attachment for spark plugs. The principal object of the invention is to provide a pair of spaced points inclosed within a glass tube whereby the condition of the spark passing through the plug on which the device is attached may be readily ascertained.

Another object of my invention is to assemble all partsin such a manner that they are rigidly held together and form a substantial airtight cavity in which the sparking may take place.

Still another object of the invention is to provide a small compact neat device which is readily attached to existing spark plugs.

With these and other objects in view my invention consists in the novel construction, combination and arrangement of parts as herein illustrated and more specifically pointed out in the appended claim.

Reference being had to the accompanying drawing forming a part of this specification,

Figure 1 is a view in side elevation showment consists of the casing 4 of glass or.

other transparent material, which I prefer to form with the globular center portion 5 havneck portions 6 on each end, and on the latter are formed semicircular an,-

nular heads 7 This member 4 is provided with These plugs are provided with smal i a ed openings 10 having in engagenttherewith the screw threaded membersll, each" of which is provided'with a conical point 12 on the inner end and screw driver slots on the outer end. The outer ends of plugs 9 are provided with the radial slots 13 for the purpose hereinafter described.

Denoted by 14 are metallic disks havin their outer edges rolled around the beads as shown at 15. A suitable gasket 16 being interposed between the glass and disk so that strains are not produced in the glass during the application of the disk thereon. The disks 14 are provided with depressed portions 17 which are adapted to enter the slots 13 in the outer portion of plug 9 whereby the latter is held in a fixed position with reference to the former. The device is attached to a spark plug 2 by means of a metallic strip 18 having openings through which extends the threaded screw 19 of the spark and one screw 11 of my device. This strip is held on the spark plug by means of the vnut 20, by which the cable connection is ordinarily held in position and is held against the disk 14 by means of a suitable nut 21. The terminals 23 of. the conducting member 22, which is normally attached over the screw 19, is removed therefrom and placed over the member 11 on the opposite end of my device, being held in position by means of the nut 24.

' In use the spark current passes from the cable 22 through the central screws 11- of my device over the strip 18 to the spark plug. Theconical points of the screw 11 are spaced apart so that the spark must jump between these points within the'casing 4, which being of transparent material it is always possible to see the condition of the spark. It will be appreciated that this device is sim ple and compact in construction; and-has no moving parts, which will become loosened and open the connections. When it is-"desired to adjust the spark points the screw 11 is turned by means of the screw driver slot inthe outer end thereof. This permits the screw to be turned in the plugs 9, the latter being held against rotation by means of the depressed portion 17 entering slot 13, and when the nuts 21 and 24 are screwed down tight the parts are all held in rigid relation to the disk, which in turnis permanently attached to the body.

It will 'be understood that while I have shown the deviceattached direct to a spark plug it may be located a considerable disj'tance away and connected by a cable to the dash board or other convenient position where the condition of the sparking may at all times be noted.

What I claim as new and wish to cover by 5 Letters Patent is A device of the character described comprising a transparent body portion having a central axial opening, annular beads formed on the'ends of said body, end plates 10 fixedly attached to said body by having their edges rolled around said beads, screw threaded plugs seated within said axial opening, radial slots in the outer ends of said plugs, projecting ribs on said end plates adapted to enter said slots, threaded con- 15 ducting members extending through said end plates and said plugs and having their inner ends lying adjacent each other within said opening,- and nuts on the outer end of said conducting members whereby said plugs 20 are held against the inside of said end plates.

In testimony whereof I aflix my signature.

FRANK F. HULTGREEN. 

